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  • 1
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    High Operating Temperature Midwave Quantum Dot Barrier Infrared Detector (QD-BIRD) (2012)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: The nBn or XBn barrier infrared detector has the advantage of reduced dark current resulting from suppressed Shockley-Read-Hall (SRH) recombination and surface leakage. High performance detectors and focal plane arrays (FPAs) based on InAsSb absorber lattice matched to GaSb substrate, with a matching AlAsSb unipolar electron barrier, have been demonstrated. The band gap of lattice-matched InAsSb yields a detector cutoff wavelength of approximately 4.2 ??m when operating at ~150K. We report results on extending the cutoff wavelength of midwave barrier infrared detectors by incorporating self-assembled InSb quantum dots into the active area of the detector. Using this approach, we were able to extend the detector cutoff wavelength to ~6 ?m, allowing the coverage of the full midwave infrared (MWIR) transmission window. The quantum dot barrier infrared detector (QD-BIRD) shows infrared response at temperatures up to 225 K.
    Keywords: Space Radiation
    Type: SPIE Defense and Security Symposium; Apr 23, 2012 - Apr 27, 2012; Baltimore, MD; United States
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    NASA TECHNICAL REPORTS
  • 2
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    Photoluminescence Study of Long Wavelength Superlattice Infrared Detectors (2011)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: In this paper, the relation between the photoluminescence (PL) intensity and the PL peak wavelength was studied. A linear decrease of the PL intensity with increasing cut-off wavelength of long wavelength infrared CBIRDs was observed at 77 K and the trend remained unchanged in the temperature range 10 - 77 K. This relation between the PL intensity and the peak wavelength can be favorably used for comparison of the optical quality of samples with different PL peak wavelengths. A strong increase of the width of the PL spectrum in the studied temperature interval was observed, which was attributed to thermal broadening.
    Keywords: Optics
    Type: SPIE Optics+Photonics; Aug 23, 2011 - Aug 25, 2011; San Diego, CA; United States
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    NASA TECHNICAL REPORTS
  • 3
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    Inductively Coupled Plasma Etching for Delineation of InAs/GaSb Pixels (2012)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: We developed 320x256 Complimentary Barrier Infrared (CBIRD) focal plane array (FPA) for long wave infrared (LWIR) imaging application. The FPA layers grown by molecular beam epitaxy (MBE) had 300 periods 1.9 micro m thick absorber. The CBIRD arrays showed the mean dark current density of 2.2 x 10(exp -4) A/cm2, when 128 mV bias voltage was applied. The long wave cut off was observed at 8.8 micrometers at the 50% peak and the maximum quantum efficiency was 54% at 5.6 micrometers. The arrays had 81% fill factor with 97% operability with noise equivalent difference temperature (NE(delta)T) of 18.6 mK and a mean detectivity of D*=1.3 x 10(exp 11) Hz(exp 1/2)/W.
    Keywords: Instrumentation and Photography
    Type: SPIE Optics and Photonics 2012; Aug 12, 2012 - Aug 16, 2012; San Diego, CA; United States
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  • 4
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    Complementary Barrier Infrared Detector (CBIRD) with Double Tunnel Junction Contact and Quantum Dot Barrier Infrared Detector (QD-BIRD) (2012)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: The InAs/GaSb type-II superlattice based complementary barrier infrared detector (CBIRD) has already demonstrated very good performance in long-wavelength infrared (LWIR) detection. In this work, we describe results on a modified CBIRD device that incorporates a double tunnel junction contact designed for robust device and focal plane array processing. The new device also exhibited reduced turn-on voltage. We also report results on the quantum dot barrier infrared detector (QD-BIRD). By incorporating self-assembled InSb quantum dots into the InAsSb absorber of the standard nBn detector structure, the QD-BIRD extend the detector cutoff wavelength from approximately 4.2 micrometers to 6 micrometers, allowing the coverage of the mid-wavelength infrared (MWIR) transmission window. The device has been observed to show infrared response at 225 K.
    Keywords: Instrumentation and Photography
    Type: Quantum Structured Infrared Photodetector International Conference; Jun 17, 2012 - Jun 22, 2012; Cargese Corsica; France
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  • 5
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    High-Performance LWIR Superlattice Detectors and FPA Based on CBIRD Design (2011)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: We report our recent efforts on advancing of antimonide superlattice based infrared photodetectors and demonstration of focal plane arrays based on a complementary barrier infrared detector (CBIRD) design. By optimizing design and growth condition we succeeded to reduce the operational bias of CBIRD single pixel detector without increase of dark current or degradation of quantum efficiency. We demonstrated a 1024x1024 pixel long-waveleng thinfrared focal plane array utilizing CBIRD design. An 11.5 micrometer cutoff focal plane without anti-reflection coating has yielded noise equivalent differential temperature of 53 mK at operating temperature of 80 K, with 300 K background and cold-stop. Imaging results from a recent 10 micrometer cutoff focal plane array are also presented. These results advance state-of-the art of superlattice detectors and demonstrated advantages of CBIRD architecture for realization of FPA.
    Keywords: Instrumentation and Photography
    Type: SPIE Photonics West; Jan 22, 2011 - Jan 27, 2011; San Francisco,CA; United States
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    NASA TECHNICAL REPORTS
  • 6
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    320 x 256 Complementary Barrier Infrared Detector Focal Plane Array for Long-Wave Infrared Imaging (2012)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: A 320 x 256 Complementary Barrier Infrared (CBIRD) focal plane array for long-wavelength infrared (LWIR) imaging is reported. The arrays were grown by molecular beam expitaxy (MBE) with a 300 period 1.9 um thick absorber. The mean dark current density of 2.2 x 10-4 A/cm2 was measured at an operating bias of 128 mV with a long wavelength cutoff of 8.8 ?m observed at 50% of the peak. The maximum quantum efficiency was 54% measured at 5.6 ?m. Operating at T = 80K, the array yielded an 81% fill factor with 97% operability. Good imagery with a mean noise equivalent different temperature (NE?T) of 18.6 mK and a mean detectivity of D* = 1.3 x 1011 cm-Hz1/2/W was achieved. The substrate was thinned using mechanical lapping and neither an AR coating nor a passivation layer was applied. This article provides the details of the fabrication process for achieving low-dark current LWIR CBIRD arrays. Discussion for an effective hard mask for excellent pattern transfer is given and appropriate mounting techniques for good thermal contact during the dry etching process is described. The challenges and differences between etching large 200 ?m test diodes and small 28 ?m FPA pixels are given.
    Keywords: Instrumentation and Photography
    Type: SPIE Defense and Security Symposium; Apr 23, 2012 - Apr 27, 2012; Baltimore, MD; United States
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  • 7
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    Multi-Color QWIP FPAs for Hyperspectral Thermal Emission Instruments (2012)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Infrared focal plane arrays (FPAs) covering broad mid- and long-IR spectral ranges are the central parts of the spectroscopic and imaging instruments in several Earth and planetary science missions. To be implemented in the space instrument these FPAs need to be large-format, uniform, reproducible, low-cost, low 1/f noise, and radiation hard. Quantum Well Infrared Photodetectors (QWIPs), which possess all needed characteristics, have a great potential for implementation in the space instruments. However a standard QWIP has only a relatively narrow spectral coverage. A multi-color QWIP, which is compromised of two or more detector stacks, can to be used to cover the broad spectral range of interest. We will discuss our recent work on development of multi-color QWIP for Hyperspectral Thermal Emission Spectrometer instruments. We developed QWIP compromising of two stacks centered at 9 and 10.5 ?m, and featuring 9 grating regions optimized to maximize the responsivity in the individual subbands across the 7.5-12 ?m spectral range. The demonstrated 1024x1024 QWIP FPA exhibited excellent performance with operability exceeding 99% and noise equivalent differential temperature of less than 15 mK across the entire 7.5-12 ?m spectral range.
    Keywords: Instrumentation and Photography
    Type: SPIE Optics and Photonics 2012; Aug 12, 2012 - Aug 16, 2012; San Diego, CA; United States
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    NASA TECHNICAL REPORTS
  • 8
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    Minority Carrier Lifetime and Photoluminescence Studies of Antimony-Based Superlattices (2012)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: In this paper, we have used the OMR technique to study the minority carrier lifetimes in three InAs/GaSb-photoluminescence (PL) structures with different number of periods in the absorber: 300, 400 and 600 periods respectively. The feasibility of using a visible 643 nm laser source with short penetration depth for lifetime measurements was studied by comparing the achieved results to measurements performed on the same samples with a 1550 nm IR laser source, which penetrates much deeper into the sample. Despite the differences in excitation wavelengths and penetration depths, the results from both measurements were very similar. This indicates that the diffusion length is long enough to facilitate a homogeneous distribution of excess carriers in the material.
    Keywords: Optics
    Type: SPIE Optics and Photonics 2012; Aug 12, 2012 - Aug 16, 2012; San Diego, CA; United States
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  • 9
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    Superlattice Barrier Infrared Detector Development at the Jet Propulsion Laboratory (2011)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: We report recent efforts in achieving state-of-the-art performance in type-II superlattice based infrared photodetectors using the barrier infrared detector architecture. We used photoluminescence measurements for evaluating detector material and studied the influence of the material quality on the intensity of the photoluminescence. We performed direct noise measurements of the superlattice detectors and demonstrated that while intrinsic 1/f noise is absent in superlattice heterodiode, side-wall leakage current can become a source of strong frequency-dependent noise. We developed an effective dry etching process for these complex antimonide-based superlattices that enabled us to fabricate single pixel devices as well as large format focal plane arrays. We describe the demonstration of a 1024x1024 pixel long-wavelength infrared focal plane array based the complementary barrier infrared detector (CBIRD) design. An 11.5 micron cutoff focal plane without anti-reflection coating has yielded noise equivalent differential temperature of 53 mK at operating temperature of 80 K, with 300 K background and cold-stop. Imaging results from a recent 10 ?m cutoff focal plane array are also presented.
    Keywords: Instrumentation and Photography
    Type: SPIE Defense, Security and Sensing 2011; Apr 25, 2011 - Apr 29, 2011; Orlando, FL; United States
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    NASA TECHNICAL REPORTS
  • 10
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    Mid- and Long-IR Broadband Quantum Well Photodetector (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: A single-stack broadband quantum well infrared photodetector (QWIP) has been developed that consists of stacked layers of GaAs/AlGaAs quantum wells with absorption peaks centered at various wavelengths spanning across the 9- to-11- m spectral regions. The correct design of broadband QWIPs was a critical step in this task because the earlier implementation of broadband QWIPs suffered from a tuning of spectral response curve with an applied bias. Here, a new QWIP design has been developed to overcome the spectral tuning with voltage that results from non-uniformity and bias variation of the electrical field across the detector stacks with different absorption wavelengths. In this design, a special effort has been made to avoid non-uniformity and bias tuning by changing the doping levels in detector stacks to compensate for variation of dark current generation rate across the stacks with different absorption wavelengths. Single-pixel photodetectors were grown, fabricated, and tested using this new design. The measured dark current is comparable with the dark measured current for single-color QWIP detectors with similar cutoff wavelength, thus indicating high material quality as well as absence of performance degradation resulting from broadband design. The measured spectra clearly demonstrate that the developed detectors cover the desired special range of 8 to 12 m. Moreover, the shape of the spectral curves does not change with applied biases, thus overcoming the problem plaguing previous designs of broadband QWIPs.
    Keywords: Man/System Technology and Life Support
    Type: NPO-48398 , NASA Tech Briefs, May 2012; 32
    Format: application/pdf
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